49ers receiver Brandon Aiyuk continues to rehab from tearing his ACL and MCL in October of last season.

With Aiyuk still on the physically unable to perform list, General Manager John Lynch noted in a Thursday interview with KNBR that there is not a true timetable for Aiyuk’s return to play.

“There’s just steps you have to continue to hit, and I’ll continue to say that Brandon is doing well in his rehab,” Lynch said, via David Bonilla of 49erswebzone.com. “Do we have an exact date right now? No. I don’t think it will be Week 1, but hopefully, I’m surprised. We’ll see.

“Continuing to try to watch him work his way through this rehab. But again, we want him fully healthy. He had a significant injury, and so, you have to do a significant rehab, and he’s doing a really good job of that, and we’ve got to continue to do so.”

If Aiyuk is on the reserve/PUP list to start the season, he’ll miss at least the first four games. The 49ers also play the Rams on Thursday night in Week 5, which could make Aiyuk’s return more likely for Week 6, if that’s the case.